To reduce wind flow resistance and drag on a trailer, truck, semitrailer, or other vehicle, side skirts have been used which extend downwardly from a bottom of the trailer and/or chassis toward the roadway to partially enclose the floor assembly and undercarriage.
Air flow passing under a ground vehicle imparts a drag force to the vehicle when it impinges the vehicle undercarriage components attached to or part of the underside of a vehicle. Side skirt systems are designed to prevent or control the flow of air from entering the undercarriage region from the side of the ground vehicle, such as a trailer of a tractor-trailer truck system, for example. Certain aerodynamic undercarriage systems are designed to prevent or minimize flow of air under the trailer from impinging on the rear wheel assembly, or bogie, of the ground vehicle. Such reduction on the drag of the ground vehicle may operate to conserve fossil fuels as well as other sources of vehicle drive power for hybrid vehicles, battery-operated vehicles, and alternative fuel-based vehicles, for example.